Re: Are graded clinical signs more reliable than dichotomized?

"Roland" <rolandersson@xxxxxxxxx> wrote in news:1151478778.585119.74760
@x69g2000cwx.googlegroups.com:

My question is a bit different. I am talking about clinical signs that
are not measured on a continous scale but usually regarded as
qualitative, ie either present or not. However in reality most clinical
signs present with varying intensity and there is always a grayzone.
Different examiners have different "cutoff" for when they decide that
tenderness is present or not making such clinical examinations
unreliable.

For patients subjective experience of pain we are used to the visual
analog scale to grade the pain.

In my research I have used graded scales of clinical signs like
tenderness and assume that this will result in more reliable
assessments, but I wonder if there is any previous research which have
examined the reliability between examiners for qualitative data which
are graded rather than dichotome?

There is quite a bit of research on such questions in the medical
literature. I am pretty sure that you can find earlier work on inter-
rater reliability in scoring the intensity of heart murmurs, classifying
NYHA functional class, grading regurgitant severity on color Doppler
echocardiograms, and many other ordinal scales of severity. The usual
test is one or another of the many kappa statistics.

PubMed search on:
"inter-rater reliability" kappa ...produces 288 hits, while
adding review as a limiter drops the number to 29.

In the Clinical Search page with settings for Diagnosis and Broad:
ordinal scales review ... produces 14 hits.

I think I saw a posting of yours to the Medstats newsgroup. It's a real
treat to read that group of mostly British statisticians. If the above
search does not get you started adequately, then you might want to post a
follow-up in Medstats as well as here.

--
David Winsemius
.